Get 20M+ Full-Text Papers For Less Than $1.50/day. Start a 7-Day Trial for You or Your Team.

Learn More →

Indole‐3‐glycerolphosphate synthase, a branchpoint for the biosynthesis of tryptophan, indole, and benzoxazinoids in maize

Indole‐3‐glycerolphosphate synthase, a branchpoint for the biosynthesis of tryptophan, indole,... The maize (Zea mays) genome encodes three indole‐3‐glycerolphosphate synthase enzymes (IGPS1, 2, and 3) catalyzing the conversion of 1‐(2‐carboxyphenylamino)‐l‐deoxyribulose‐5‐phosphate to indole‐3‐glycerolphosphate. Three further maize enzymes (BX1, benzoxazinoneless 1; TSA, tryptophan synthase alpha subunit; and IGL, indole glycerolphosphate lyase) convert indole‐3‐glycerolphosphate to indole, which is released as a volatile defense signaling compound and also serves as a precursor for the biosynthesis of tryptophan and defense‐related benzoxazinoids. Phylogenetic analyses showed that IGPS2 is similar to enzymes found in both monocots and dicots, whereas maize IGPS1 and IGPS3 are in monocot‐specific clades. Fusions of yellow fluorescent protein with maize IGPS enzymes and indole‐3‐glycerolphosphate lyases were all localized in chloroplasts. In bimolecular fluorescence complementation assays, IGPS1 interacted strongly with BX1 and IGL, IGPS2 interacted primarily with TSA, and IGPS3 interacted equally with all three indole‐3‐glycerolphosphate lyases. Whereas IGPS1 and IGPS3 expression was induced by insect feeding, IGPS2 expression was not. Transposon insertions in IGPS1 and IGPS3 reduced the abundance of both benzoxazinoids and free indole. Spodoptera exigua (beet armyworm) larvae show improved growth on igps1 mutant maize plants. Together, these results suggest that IGPS1 and IGPS3 function mainly in the biosynthesis of defensive metabolites, whereas IGPS2 may be involved in the biosynthesis of tryptophan. This metabolic channeling is similar to, though less exclusive than, that proposed for the three maize indole‐3‐glycerolphosphate lyases. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png The Plant Journal Wiley

Indole‐3‐glycerolphosphate synthase, a branchpoint for the biosynthesis of tryptophan, indole, and benzoxazinoids in maize

Loading next page...
 
/lp/wiley/indole-3-glycerolphosphate-synthase-a-branchpoint-for-the-biosynthesis-978aSycc0C

References (67)

Publisher
Wiley
Copyright
Copyright © 2021 John Wiley & Sons Ltd and the Society for Experimental Biology
ISSN
0960-7412
eISSN
1365-313X
DOI
10.1111/tpj.15163
Publisher site
See Article on Publisher Site

Abstract

The maize (Zea mays) genome encodes three indole‐3‐glycerolphosphate synthase enzymes (IGPS1, 2, and 3) catalyzing the conversion of 1‐(2‐carboxyphenylamino)‐l‐deoxyribulose‐5‐phosphate to indole‐3‐glycerolphosphate. Three further maize enzymes (BX1, benzoxazinoneless 1; TSA, tryptophan synthase alpha subunit; and IGL, indole glycerolphosphate lyase) convert indole‐3‐glycerolphosphate to indole, which is released as a volatile defense signaling compound and also serves as a precursor for the biosynthesis of tryptophan and defense‐related benzoxazinoids. Phylogenetic analyses showed that IGPS2 is similar to enzymes found in both monocots and dicots, whereas maize IGPS1 and IGPS3 are in monocot‐specific clades. Fusions of yellow fluorescent protein with maize IGPS enzymes and indole‐3‐glycerolphosphate lyases were all localized in chloroplasts. In bimolecular fluorescence complementation assays, IGPS1 interacted strongly with BX1 and IGL, IGPS2 interacted primarily with TSA, and IGPS3 interacted equally with all three indole‐3‐glycerolphosphate lyases. Whereas IGPS1 and IGPS3 expression was induced by insect feeding, IGPS2 expression was not. Transposon insertions in IGPS1 and IGPS3 reduced the abundance of both benzoxazinoids and free indole. Spodoptera exigua (beet armyworm) larvae show improved growth on igps1 mutant maize plants. Together, these results suggest that IGPS1 and IGPS3 function mainly in the biosynthesis of defensive metabolites, whereas IGPS2 may be involved in the biosynthesis of tryptophan. This metabolic channeling is similar to, though less exclusive than, that proposed for the three maize indole‐3‐glycerolphosphate lyases.

Journal

The Plant JournalWiley

Published: Apr 1, 2021

Keywords: ; ; ; ; ; ;

There are no references for this article.